Apparatus and method for cryogranulating a pharmaceutical composition

ABSTRACT

Cryogranulation systems with improved dispenser assemblies are provided for use in manufacturing frozen pellets of pharmaceutical substances in a fluid medium. Methods of cryogranulating the pharmaceutical substance in the fluid medium are also provided. In particular embodiments, the dispenser assembly is used with suspensions or slurries of pharmaceutical compositions including biodegradable substances, such as proteins, peptides, and nucleic acids. In certain embodiments, the pharmaceutical substance can be adsorbed to any pharmaceutically acceptable carrier particles suitable for making pharmaceutical powders. In one embodiment, the pharmaceutical carrier can be, for example, diketopiperazine-based microparticles. The dispenser assembly improves the physical characteristics of the cryopellets formed and minimizes product loss during processing.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.14/065,609, filed Oct. 29, 2013, which is a continuation of U.S. patentapplication Ser. No. 12/917,623, filed Nov. 2, 2010, which claimspriority based on Provisional Application Ser. No. 61/257,385, filedNov. 2, 2009, which are hereby incorporated by reference in theirentirety.

TECHNICAL FIELD

This invention relates to an improved apparatus and a method forcryogranulating a pharmaceutical composition during manufacturing of adrug product. In a particular embodiment, the apparatus and method areutilized in a process for manufacturing pharmaceutical products forpulmonary delivery.

BACKGROUND

Cryogranulation equipment is commercially available for the manufactureof frozen product pellets in the food industry. In particular,cryogranulation systems used in the food industry are suitable forpreparing frozen foods, such as ice cream. U.S. Pat. Nos. 6,216,470;7,062,924, and 7,475,554, for example, disclose systems used forcryogranulation, which disclosures are incorporated herein by reference.

Cryogranulation systems may include a tray or channel carrying a flow ofa cryogenic liquid, such as liquid nitrogen. A material to becryogranulated is introduced into the flow of liquid nitrogen from adispenser positioned above the tray. The material is frozen by theliquid nitrogen into pellets or granules. At the end of the tray, theliquid nitrogen and the frozen pellets are separated, typically using ascreen. The liquid nitrogen is returned to the upper end of the tray toform a closed loop circulation of liquid nitrogen. The frozen pelletsmay be used as is or subjected to further processing. The terms“cryogranulating” and “cryopelletizing” are used more or lessinterchangeably.

Some processes, such as manufacturing of pharmaceutical formulations,require precise control and repeatable results. Prior artcryogranulation systems have not heretofore been suitable formanufacturing of pharmaceutical formulations. Accordingly, there is aneed for improvements in the design and manufacture of cryogranulationsystems and methods for use in manufacturing of pharmaceuticalformulations.

SUMMARY

The present invention relates to cryogranulation systems with animproved dispenser assembly for use in manufacturing frozen pellets ofpharmaceutical substances in a fluid medium. Methods of cryogranulatingthe pharmaceutical substance in the fluid medium are also disclosed. Inparticular embodiments, the dispenser assembly is used with suspensionsor slurries of pharmaceutical compositions comprising biodegradablesubstances, such as proteins, peptides, and nucleic acids. In certainembodiments, the pharmaceutical substance can be adsorbed to anypharmaceutically acceptable carrier particles suitable for makingpharmaceutical powders. In one embodiment, the pharmaceutical carriercan be, for example, diketopiperazine-based microparticles.

According to a first aspect of the invention, a cryogranulation systemis provided. The cryogranulation system comprises at least one trayconfigured to carry a flow of a cooling agent; a mechanism configured todeliver the cooling agent to the at least one tray; a dispenser assemblyconfigured to supply a pharmaceutical composition into the coolingagent, the dispenser assembly including a housing and a dispensersubassembly, the housing configured to mount the dispenser subassemblyabove the tray, the dispenser subassembly including an enclosuredefining an interior chamber, at least one inlet port for supplying thepharmaceutical composition to the interior chamber and a plurality ofdispenser ports for supplying the pharmaceutical composition to thecooling agent in the tray, the dispenser ports being configured toproduce, after interaction of the pharmaceutical composition with thecooling agent, pellets of the pharmaceutical composition in apredetermined size range; and a transport assembly configured toseparate the pellets from the cooling agent and to transport the pelletsto a pellet receptacle.

According to a second aspect of the invention, a dispenser assembly isprovided for supplying a pharmaceutical composition into a cooling agentin a cryogranulation system. The dispenser assembly comprises a housingand a dispenser subassembly, the housing configured to mount thedispenser subassembly above the cooling agent, the dispenser subassemblyincluding an enclosure defining an interior chamber, at least one inletport for supplying the pharmaceutical composition to the interiorchamber and a plurality of dispenser ports for supplying thepharmaceutical composition to the cooling agent, the dispenser portsbeing configured to produce, after interaction of the pharmaceuticalcomposition with the cooling agent, pellets of the pharmaceuticalcomposition in a predetermined size range.

According to a third aspect of the invention, a method is provided forcryogranulating a pharmaceutical composition. The method comprisesestablishing a flow of a cooling agent; supplying a pharmaceuticalcomposition to a dispenser assembly; dispensing the pharmaceuticalcomposition from the dispenser assembly into the flow of cooling agent,the pharmaceutical composition being dispensed uniformly over the flowof cooling agent and with a droplet size to form pellets in apredetermined size range; and separating the pellets from the coolingagent.

According to a fourth aspect of the invention, a dispenser assemblycomprises a housing having an internal volume or chamber, a cover, and adispenser subassembly attachable to the housing. The dispensersubassembly is configured to have an outer surface and an internalsurface, a top portion and bottom portion, the top portion having aninlet port configured to communicate with the internal chamber of thedispenser subassembly. The inlet port provides a conduit for deliveringto the dispenser subassembly a pharmaceutical substance in a fluidmedium. The dispenser subassembly is further configured with a pluralityof outlet ports located at the bottom of the dispenser assembly.

According to a fifth aspect of the invention, a method forcryopelletizing a suspension or a slurry is provided. The methodcomprises pumping a pharmaceutical composition at a rate of about 0.5 toabout 10 liters per minute using a peristaltic pump through a dispenserassembly comprising a dispenser subassembly having two portions, a firstelement and a second element; the first element forming the top portionof the device and having one or more inlet ports for providing theliquid pharmaceutical composition and a second element forming thebottom portion of the dispenser subassembly and comprising channelswhich are provided with a plurality of conduits and dispensing ports;both first and second elements forming an enclosure for holding a volumeof a fluid and capable of dispensing said fluid in droplet form.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference is madeto the accompanying drawings, which are incorporated herein by referenceand in which:

FIG. 1 is a schematic block diagram of a cryogranulation system inaccordance with embodiments of the invention;

FIG. 2 is a partial cross-sectional view of the cryogranulation systemof FIG. 1, showing the dispenser assembly and the upper tray carrying acooling agent;

FIG. 3 is an isometric, partially cut-away view of the dispenserassembly of FIG. 1, in accordance with embodiments of the invention;

FIG. 4 is an isometric, exploded view of the dispenser assembly of FIG.3;

FIG. 5 is a bottom view of the dispenser assembly;

FIG. 6 is an isometric view of the dispenser subassembly shown in FIG.4; and

FIG. 7 is a cross-sectional view of the dispenser subassembly.

DETAILED DESCRIPTION

Cryogranulation equipment cannot be readily applied to the manufacturingof pharmaceutical compositions in the freeze-dry step of biological drugproducts processing without encountering many problems. Withoutpelletizing a pharmaceutical composition, the freezing processagglomerates the composition and leads to increased lyophilization timesof the drug product. Other problems encountered when using off the shelfcryogranulation equipment in a pharmaceutical manufacturing process,include: lack of pellet formation, streaming and freezing of thesolutions and/or suspensions containing the pharmaceutical substanceprior to dispensing, which leads to clogging of the dispenser apparatus,and therefore, product loss during transport due to inability to createthe desired pellet sizes during pelletization. The standardcryogranulation equipment is typically used with substances ofrelatively high viscosity.

Disclosed herein are an apparatus and methods for cryogranulating orcryopelletizing a pharmaceutical composition. The pharmaceuticalcomposition may have the form of a pharmaceutical substance in a fluidmedium. In a particular embodiment, the cryogranulation system producespellets with more homogeneous pellet sizes, which are suitable fortransporting through a transport system, improving the efficiency of theprocess and drug product yield.

In one embodiment, the cryogranulation system produces a more homogenouspellet size of any diameter depending on the pharmaceutical substanceand the fluid medium to be pelletized. In certain embodiments, thegranules or pellets can range from about 3 to 6 mm in diameter. In aparticular embodiment, the cryogranulation system includes an improveddispenser assembly that can be adapted to existing commerciallyavailable cryogranulation systems.

In particular embodiments, the pharmaceutical substance can be a proteinor peptide which is adsorbed onto carrier particles and contained in amedium such as a buffer, a solution, a suspension or a slurry.

In one embodiment, the pharmaceutical substance may comprise, forexample, a diketopiperazine and a pharmaceutically active ingredient. Inthis embodiment, the pharmaceutically active ingredient or active agentcan be any type depending on the disease or condition to be treated. Inanother embodiment, the diketopiperazine can include, for example,symmetrical molecules and asymmetrical diketopiperazines having utilityto form particles, microparticles and the like, which can be used ascarrier systems for the delivery of active agents to a target site inthe body. The term ‘active agent’ is referred to herein as thetherapeutic agent, or molecule such as protein or peptide or biologicalmolecule, to be encapsulated, associated, joined, complexed or entrappedwithin or adsorbed onto the diketopiperazine formulation. Any form of anactive agent can be combined with a diketopiperazine. The drug deliverysystem can be used to deliver biologically active agents havingtherapeutic, prophylactic or diagnostic activities.

One class of drug delivery agents that has been used to producemicroparticles that overcome problems in the pharmaceutical arts such asdrug instability and/or poor absorption, are the 2,5-diketopiperazines.2,5-diketopiperazines are represented by the compound of the generalFormula 1 as shown below where E=N. One or both of the nitrogens can bereplaced with oxygen to create the substitution analogs diketomorpholineand diketodioxane, respectively.

These 2,5 diketopiperazines have been shown to be useful in drugdelivery, particularly those bearing acidic R groups (see for exampleU.S. Pat. No. 5,352,461 entitled “Self Assembling Diketopiperazine DrugDelivery System;” U.S. Pat. No. 5,503,852 entitled “Method For MakingSelf-Assembling Diketopiperazine Drug Delivery System;” U.S. Pat. No.6,071,497 entitled “Microparticles For Lung Delivery ComprisingDiketopiperazine;” and U.S. Pat. No. 6,331,318 entitled“Carbon-Substituted Diketopiperazine Delivery System,” each of which isincorporated herein by reference in its entirety for all that it teachesregarding diketopiperazines and diketopiperazine-mediated drugdelivery). Diketopiperazines can be formed into drug adsorbingmicroparticles. This combination of a drug and a diketopiperazine canimpart improved drug stability and/or absorption characteristics. Thesemicroparticles can be administered by various routes of administration.As dry powders these microparticles can be delivered by inhalation tospecific areas of the respiratory system, including the lung.

The fumaryl diketopiperazine(bis-3,6-(N-fumaryl-4-aminobutyl)-2,5-diketopiperazine; FDKP) is onepreferred diketopiperazine for pulmonary applications:

FDKP provides a beneficial microparticle matrix because it has lowsolubility in acid but is readily soluble at neutral or basic pH. Theseproperties allow FDKP to crystallize under acidic conditions and thecrystals self-assemble to form particles. The particles dissolve readilyunder physiological conditions where the pH is neutral. In oneembodiment, the microparticles disclosed herein are FDKP microparticlesloaded with an active agent such as insulin.

In some embodiments, the carrier particles can comprise otherdiketopiperazines, including fumaryl diketopiperazine, succinyldiketopiperazine, maleyl diketopiperazine and the like. In certainembodiments, the process can generate granules or pellets that can begreater than 4 mm or greater 5 mm in diameter.

The cryogranulation system described herein includes a dispenserassembly, a reservoir for holding a source of a cooling agent such asliquid nitrogen, a pump assembly for delivering the pharmaceuticalcomposition, a pump system for delivering the cooling agent, and atransport system for transporting formed pellets to a pellet receptacle.The dispenser assembly is configured of any size depending on themanufacturing needs and is installed proximal to the cooling agent sothat the distance from the surface of the cooling agent is within a fewinches from the dispensing ports forming the droplets of pharmaceuticalcomposition to be cryogranulated. In a particular embodiment, thedispenser assembly may be placed in the cryogranulation system withinabout 2 cm from the liquid nitrogen flow. Other dispenser heights in arange of about 2 cm to about 25 cm can be utilized depending on thesubstance to be cryogranulated.

A schematic block diagram of a cryogranulation system in accordance withembodiments of the invention is shown in FIGS. 1 and 2. The supportingstructure for the components of cryogranulation system 10 is omitted inFIGS. 1 and 2. The cryogranulation system 10 may be a modification of acommercially available cryogranulation system manufactured and sold byCES Inc.

A cryogranulation system 10 may include an upper tray 12, a lower tray14 and a conveyor 20. Each of trays 12 and 14 may be U-shaped, as shownin FIG. 2, to carry a cooling agent, such as a cryogenic liquid,preferably liquid nitrogen 24. Each of trays 12 and 14 may be tiltedwith respect to horizontal to cause the liquid nitrogen 24 to flowdownwardly. The angles of trays 12 and 14 may be selected to produce adesired flow rate of liquid nitrogen 24. The trays 12 and 14 may beopen-ended, at least at their lower ends, to permit unrestricted flow ofliquid nitrogen 24.

Cryogranulation system 10 further includes a liquid nitrogen reservoir30 located under conveyor 20 and near the lower end of lower tray 14.Liquid nitrogen reservoir 30 collects the liquid nitrogen 24 that dropsfrom the lower end of lower tray 14. The liquid nitrogen is supplied bya pump 32 from reservoir 30 to the upper end of upper tray 12 to providea closed loop system for circulation of liquid nitrogen. The liquidnitrogen 24 flows down upper tray 12 and lower tray 14, and then returnsto liquid nitrogen reservoir 30.

A dispenser assembly 50 dispenses a pharmaceutical composition 52 intothe flow of liquid nitrogen 24 in upper tray 12. The pharmaceuticalcomposition is supplied from a source tank 54 by a pump 56 to dispenserassembly 50. The pump 56 may be a peristaltic pump and, in someembodiments, may pump the pharmaceutical composition 52 at a flow rateof about 0.5 to about 10 liters per minute. A nitrogen gas source 60 maysupply nitrogen gas to dispenser assembly 50.

In operation, the upper tray 12, the lower tray 14, the liquid nitrogenreservoir 30 and pump 32 produce a continuous flow of liquid nitrogen 24in trays 12 and 14. The dispenser assembly 50 dispenses thepharmaceutical composition 52 into the flow of liquid nitrogen, asdescribed below. The pharmaceutical composition forms frozen pelletswhich flow with the liquid nitrogen and drop from the lower end of lowertray 14 onto conveyor 20.

Conveyor 20 performs the functions of separating the frozen pellets fromthe liquid nitrogen and transporting the pellets to a pellet receptacle62. Conveyor 20 may be in the form of a screen or mesh having openingssized to pass the liquid nitrogen 24 and to retain the pellets of thepharmaceutical composition. The liquid nitrogen 24 drops through theconveyor 20 into liquid nitrogen reservoir 30. The frozen pellets arecarried by the conveyor 20 and drop from conveyor 20 into pelletreceptacle 62.

An embodiment of dispenser assembly 50 is shown in FIGS. 3-7. FIG. 3 isan isometric view of dispenser assembly 50 with side walls of thehousing partially cut away. FIG. 4 is an exploded isometric view ofdispenser assembly 50. FIG. 5 is a bottom view of dispenser assembly 50.FIG. 6 is an isometric view of the dispenser subassembly. FIG. 7 is across-sectional view of the dispenser subassembly. Like elements inFIGS. 3-7 have the same reference numerals.

Dispenser assembly 50 may include a housing 100 and a dispensersubassembly 120 mounted in housing 100. Housing 100 may include an upperhousing member 110, a lower housing member 112 and a cover 114. Thehousing 100 serves to mount dispenser subassembly 120 above upper tray12 of cryogranulation system 10 (FIG. 1). The dispenser assembly 50 canbe made of, for example, stainless steel, however other materials suchas metal or plastic composites can be used.

As shown in FIG. 4, upper housing member 110 includes four side walls130 that define a chamber 115 and a flange 132 at the upper end of sidewalls 130. Flange 132 may be provided with mounting holes 134 formounting dispenser assembly 50 in the cryogranulation system 10 and maybe further provided with handles 136 to facilitate installation andremoval of dispenser assembly 50.

Cover 114 may be sized to cover an opening in the upper end of upperhousing member 110. Cover 114 may be provided with openings 116 tosupply a gas, such as nitrogen gas, into chamber 115.

Lower housing member 112 may be dimensioned for mounting at the lowerend of side walls 130 so as to close the lower end of chamber 115. Inaddition, lower housing member 112 is provided with an opening 140 forinstallation of dispenser subassembly 120, with dispenser ports ofdispenser subassembly 120 exposed for dispensing the pharmaceuticalcomposition 52 into the liquid nitrogen 24.

As shown in FIGS. 5-7, the dispenser subassembly 120 includes a topportion 150 and a bottom portion 152 forming an enclosure having aninterior chamber 158 for holding the pharmaceutical composition to becryogranulated. The top portion 150 of dispenser subassembly 120 mayhave a relatively flat configuration and includes one or more inletports 154, 156 configured to communicate with the interior chamber 158of the dispenser subassembly. The inlet ports 154, 156 provide conduitsfor delivering the pharmaceutical composition to be cryogranulated. Insome embodiments, two or more inlet ports can be provided on top portion150 so that the pharmaceutical composition is distributed throughout theinterior chamber 158 of dispenser subassembly 120. The additional inletports can be spaced along the top portion 150 of dispenser subassembly120 and can provide a uniform distribution of the pharmaceuticalcomposition.

The bottom portion 152 of the dispenser subassembly 120 is configuredhaving one or more interior channels 160 or depressions. Dispenser ports170 provide fluid communication between the interior channels 160 andthe exterior of the dispenser subassembly 120 (FIG. 7) for dispensing ofthe pharmaceutical composition. Each of the dispenser ports 170 includesa conduit 162 between channel 160 and an outlet of dispenser port 170.Conduits 162 can be of any length, depending on the solution orsuspension to be cryopelletized. However, in one embodiment, the lengthof conduit 162 is from 1 to 3 mm and the opening of dispenser port 170can be greater than about 3 mm in diameter. In other embodiments, thenumber of dispenser ports can vary. In some embodiments, the dispenserports 170 are aligned within the channels 160 of the bottom portion 152of the dispenser subassembly 120 forming rows 172, 174 (FIG. 5) ofdispenser ports 170. In some embodiments, the dispenser subassembly 120may have at least two channels 160 and at least two rows 172, 174 ofdispenser ports 170. In some embodiments, the dispenser ports 170 can beconfigured to form an acute angle with reference to vertical. In someembodiments, the dispenser ports 170 may be located about one to fourinches above the liquid nitrogen 24 and preferably about one to twoinches above the liquid nitrogen.

As shown in FIG. 7, each conduit 162 interconnecting channel 160 anddispenser port 170 may include an upper conduit 200 of a first diameterand a lower conduit 202 of a second diameter. In some embodiments wherethe dispenser subassembly is used for dispensing diketopiperazine-basedmicroparticles, the upper conduit 200 may have a diameter of about 1 mmand the lower conduit 202 may have a diameter of about 3 mm. Moregenerally, the upper conduit 200 may have a diameter of about 1 mm orgreater based on desired droplet size.

As further shown in FIG. 7, each upper conduit 200 may have a verticalorientation and each lower conduit 202 may be oriented at an acuteangle, such as a range of 0 degrees to less than 90 degrees, withrespect to vertical. Also, the lower conduits 202 in row 172 and thelower conduits 202 in row 174 are oriented at opposite angles withrespect to vertical.

Spaced-apart rows 172 and 174 of dispenser ports 170 are shown in FIG.5. The rows 172 and 174 of dispenser ports 170 may be perpendicular tothe flow direction of liquid nitrogen 24 in upper tray 12 (FIG. 1) andmay extend across substantially the entire width of upper tray 12 (FIG.2). In some embodiments, the spacing between dispenser ports 170 in rows172, 174 is about 13 mm. Further, the dispenser ports 170 in row 172 maybe offset from the dispenser ports 170 in row 174, for example byone-half the spacing between dispenser ports 170.

The configuration of dispenser ports 170 described above providesuniform dispensing of the pharmaceutical substance from dispenserassembly 50 into liquid nitrogen 24 with a desired droplet size. Therisk of interference between droplets dispensed from different dispenserports 170 is limited by the angled passages 202, and uniformdistribution is enhanced by the configuration of offset rows ofdispenser ports 170.

A securing mechanism including, but not limited to, clamps, bolts can beused to hold top portion 150 and bottom portion 152 of the dispensersubassembly 120 together. In one embodiment, clamps 180 are used tosecure the parts of dispenser subassembly 120. Inlet ports 154, 156 canbe connected by tubes or hoses, for example, to pump 54 (FIG. 1) todeliver the pharmaceutical composition to the dispenser subassembly.

The dispenser assembly 50 can be provided with a heater, such as aresistive heater, which can be attached to the housing to prevent thesolution from freezing during dispensing.

In one embodiment, the process for cryogranulating a pharmaceuticalcomposition comprises dissolving a pharmaceutical substance in a liquid,including a solvent, buffer, water, saline; mixing the solution orsuspension; pumping the suspension through a cryogenic dispenserassembly under nitrogen gas into a cooling agent such as liquidnitrogen, and collecting the granules or pellets formed in a dewar; andtransporting said pellets to a container. In one aspect of thisembodiment, the pharmaceutical composition comprises microparticles of adiketopiperizine, for example, particles of fumaryl diketopiperazine anda peptide, polypeptide or protein, or a nucleic acid in a suspension orslurry. For example, the diketopiperazine microparticles can comprisecompounds, including but not limited to a peptide such as endocrinepeptides such as insulin, GLP-1, oxyntomodulin, parathyroid hormone, andcalcitonin.

The rate of flow of the liquid solution or suspension through thedispenser depends on the type of formulation used. The rate of flowthrough the dispenser is controlled by the pump systems settings. Inparticular embodiments when using a diketopiperazine-basedpharmaceutical suspension, the pump is run at rpm settings ranging fromabout 50 to about 100 rpms, which can generate flow rates ranging fromabout 0.5 to about 10 liters per minute through the dispenser assembly.

The following example describes the process for cryogranulating apharmaceutical substance and it is intended to be illustrative of thedisclosure of the apparatus and process described herein.

Example 1

Test runs were conducted to determine the uniformity of the pelletsproduced with the disclosed dispenser assembly. A suspension of fumaryldiketopiperazine (FDKP) microparticles with and without insulin werecryopelletized using a cryogranulator obtained from CES, Inc. Thestandard dispenser was removed and replaced with the dispenser assemblydescribed herein.

FDKP suspension in a mild acetic acid solution alone or containinginsulin adsorbed onto the particles in a suspension were cryopelletizedin the dispenser assembly of the present invention. The peristaltic pump(Watson-Marlow) was run at 100 rpm and the suspension containing about400 kg of FDKP particles or FDKP-insulin particles were pumped throughthe dispenser at a flow rate of about 1.5 l/min. A nitrogen gas blanketis pumped into the housing chamber while the equipment is running.

Tables 1, 2 and 3 show data obtained from the experiments. Pellet sizeand content were determined from batch product from a known amount orweight as measured by a series of sieves ranging from larger openings of4.75 mm and 3.35 mm followed by determination of the weights from eachsieve.

TABLE 1 FDKP particles in suspension in CES, Inc. cryogranulator Pelletsize Batch No 1 (% of Total) Batch 2 (% of total) >4.75 mm 2 3 4.75mm-3.35 mm 82 46 <3.35 mm 16 50

TABLE 2 FDKP particles in suspension using CES, Inc. cryogranulator withimproved dispenser assembly Batch 2 Batch 2 Batch No. 1 Batch No. 1Dewar 12 Dewar 54 Dewar 5 Dewar 21 (% of (% of Pellet size (% of Total)(% of Total) total) total) >4.75 mm 44 67 50 54 4.75 mm-3.35 mm 27 23 4037 <3.35 mm 9 10 9 10

TABLE 3 FDKP-insulin particles in suspension using CES, Inc.cryogranulator with improved dispenser assembly Batch 1 Batch 1 Batch 2Batch 2 Batch 3 Batch 3 Pellet size Dewar 25 Dewar 125 Dewar 25 Dewar130 Dewar 12 Dewar 125 >4.75 mm 48 45 41 47 59 53 4.75 mm- 42 36 47 3329 25 3.35 mm <3.35 mm 10 18 12 20 12 22

As seen in Tables 1, 2 and 3 the percent of pellet size greater than4.75 mm diameter is significantly increased with the dispenser assemblydescribed herein.

The dispenser assembly described herein creates a more consistent pelletsize distribution, minimizes the formation of pellet fines during thecryogranulation process and eliminates dispenser freezing problems thatwere present with commercially available cryogranulation equipment.

The preceding disclosures are illustrative embodiments. It should beappreciated by those of skill in the art that the techniques disclosedherein elucidate representative techniques that function well in thepractice of the present disclosure. However, those of skill in the artshould, in light of the present disclosure, appreciate that many changescan be made in the specific embodiments that are disclosed and stillobtain a like or similar result without departing from the spirit andscope of the invention.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, reaction conditions,and so forth used in the specification and claims are to be understoodas being modified in all instances by the term “about.” Accordingly,unless indicated to the contrary, the numerical parameters set forth inthe specification and attached claims are approximations that may varydepending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques. Notwithstanding that the numerical ranges and parameterssetting forth the broad scope of the invention are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containscertain errors necessarily resulting from the standard deviation foundin their respective testing measurements.

The terms “a,” “an,” “the” and similar referents used in the context ofdescribing the invention (especially in the context of the followingclaims) are to be construed to cover both the singular and the plural,unless otherwise indicated herein or clearly contradicted by context.Recitation of ranges of values herein is merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range. Unless otherwise indicated herein, eachindividual value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention otherwise claimed. No languagein the specification should be construed as indicating any non-claimedelement essential to the practice of the invention.

Specific embodiments disclosed herein may be further limited in theclaims using consisting of or and consisting essentially of language.When used in the claims, whether as filed or added per amendment, thetransition term “consisting of” excludes any element, step, oringredient not specified in the claims. The transition term “consistingessentially of” limits the scope of a claim to the specified materialsor steps and those that do not materially affect the basic and novelcharacteristic(s). Embodiments of the invention so claimed areinherently or expressly described and enabled herein.

Groupings of alternative elements or embodiments of the inventiondisclosed herein are not to be construed as limitations. Each groupmember may be referred to and claimed individually or in any combinationwith other members of the group or other elements found herein. It isanticipated that one or more members of a group may be included in, ordeleted from, a group for reasons of convenience and/or patentability.When any such inclusion or deletion occurs, the specification is deemedto contain the group as modified thus fulfilling the written descriptionof all Markush groups used in the appended claims.

Certain embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention. Ofcourse, variations on these described embodiments will become apparentto those of ordinary skill in the art upon reading the foregoingdescription. The inventor expects skilled artisans to employ suchvariations as appropriate, and the inventors intend for the invention tobe practiced otherwise than specifically described herein. Accordingly,this invention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

Furthermore, numerous references have been made to patents and printedpublications throughout this specification. Each of the above-citedreferences and printed publications are individually incorporated hereinby reference in their entirety.

It is to be understood that the embodiments of the invention disclosedherein are illustrative of the principles of the present invention.Other modifications that may be employed are within the scope of theinvention. Thus, by way of example, but not of limitation, alternativeconfigurations of the present invention may be utilized in accordancewith the teachings herein. Accordingly, the present invention is notlimited to that precisely as shown and described.

The invention claimed is:
 1. A method for cryogranulating apharmaceutical composition, comprising: dispensing a pharmaceuticalcomposition including diketopiperazine-based microparticles in a fluidmedium into a flow of a cooling agent to produce, after interaction ofthe pharmaceutical composition with the cooling agent, pellets of thepharmaceutical composition, wherein dispensing the pharmaceuticalcomposition includes dispensing a pharmaceutical suspension through adispenser assembly into a flow of a cooling agent to form the frozenpellets, the dispenser assembly including first and second rows ofdispenser ports, the rows of dispenser ports being disposedperpendicularly with respect to the flow of the cooling agent, whereinthe dispenser ports of the first and second rows are angled with respectto vertical and wherein the dispenser ports of the first row aredisposed at opposite angles with respect to the dispenser ports of thesecond row; and separating the pellets from the cooling agent.
 2. Amethod for cryogranulating a pharmaceutical composition as defined inclaim 1, wherein 41% or more of the pellets have diameters greater than4.75 mm.
 3. A method for cryogranulating a pharmaceutical composition asdefined in claim 1, wherein 22% or less of the pellets have diametersless than 3.35 mm.
 4. A method for cryogranulating a pharmaceuticalcomposition as defined in claim 2, wherein 22% or less of the pelletshave diameters less than 3.35 mm.
 5. A method for cryogranulating apharmaceutical composition as defined in claim 1, wherein thediketopiperazine-based microparticles comprise fumaryl diketopiperazinemicroparticles.
 6. A method for cryogranulating a pharmaceuticalcomposition as defined in claim 1, wherein the diketopiperazine-basedmicroparticles comprise fumaryl diketopiperazine microparticles loadedwith a pharmaceutically active agent.
 7. A method for cryogranulating apharmaceutical composition as defined in claim 1, wherein dispensing thepharmaceutical composition comprises supplying the pharmaceuticalcomposition to an interior chamber of the dispenser assembly anddispensing the pharmaceutical composition from the interior chamberthrough the dispenser ports in the dispenser assembly.
 8. A method forcryogranulating a pharmaceutical composition as defined in claim 7,further comprising supplying nitrogen gas to the interior chamber of thedispenser assembly.
 9. A method for cryogranulating a pharmaceuticalcomposition as defined in claim 1, wherein the pellets range in diameterfrom 3-6 mm.
 10. A method for cryogranulating a pharmaceuticalcomposition as defined in claim 1, further comprising heating thepharmaceutical composition to prevent the pharmaceutical compositionfrom freezing during dispensing.